High Temperature hot water system

Tony Furst

Good afternoon gentlemen,

I have a perplexing question regarding high temperature hot water systems, we currently have a project involving three 600 Bhp HTHW generators.  Each boiler is operating at 350 degrees F and a maximum pressure of 380 PSIG, the new boiler has been fitted with dual Clark Reliance conductivity type LWCO devices mounted on top of the leaving water drum of the boiler.  We have a recurring problem that dissolved nitrogen is continuously being released and it collects in the LWCO and shuts the boiler down.  Any one have any experience with HTHW generators and how do you keep the LWCO from tripping due to the nitrogen release?  Keep in mind also that the original two boilers have no LWCO protection so they are not affected by this little aggravation.



Tony

Tom Blackwell_2

Venting

The lwco assembly is located such that it will vent into the piping, right? During the start-up of a HTHW system air will most certainly collect at the high points as it comes out of solution, and the usual means for getting this out is for it to collect in air bottles at the high points and be manually vented out. Any location that is a high point will trap air and there must be a way to get it out. If the LWCO cannot vent into a higher pipe, then it cannot serve as a safety device because the water trapped in it would not seek the level of the upper drum (full of water). Or am I misreading your post and the problem is bubbles adhered to the probe itself?

Mark Eatherton

I agree with Tom...

According to the manufacturer, they would prefer to see the probes mounted in a vertical column attached to the vessel. If the only place to mount the probes is in the top of the drum, they do have longer probes available.



If you had a collection chamber above the detector, and a probe in there, you could signal someone when the chamber needed to be manually vented to expell accumulated gasses.



Although I have only worked on one HTHW system, I am not aware of any automatic air elimination devices, and I do know when to say when.



When. :-)



ME



http://www.clarkreliance.com/site/applications/DocumentLibraryManager/upload/C9.1C%20TWIP.pdf

flange

any resloution?

on the generators we have, which also happened to be six hundies, the solution was to pipe the outlet up to the supply piping so that the dissolved nitro will flow by instead of collecting, and install the low water cutoff in a tee fitting. sort of like a bypass line. as long as the low water cutoff is in the right elevation, it will work just fine.